From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 2002:a24:ee43:: with SMTP id b64-v6mr12398698iti.3.1538419912797; Mon, 01 Oct 2018 11:51:52 -0700 (PDT) X-Received: by 2002:aca:fc85:: with SMTP id a127-v6mr194281oii.6.1538419912655; Mon, 01 Oct 2018 11:51:52 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!news.gegeweb.eu!gegeweb.org!usenet-fr.net!proxad.net!feeder1-2.proxad.net!209.85.166.216.MISMATCH!x98-v6no68833ita.0!news-out.google.com!n199-v6ni37itn.0!nntp.google.com!x188-v6no68396ite.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Mon, 1 Oct 2018 11:51:52 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=2a02:c7d:3c35:b000:325a:3aff:fe0f:37a5; posting-account=L2-UcQkAAAAfd_BqbeNHs3XeM0jTXloS NNTP-Posting-Host: 2a02:c7d:3c35:b000:325a:3aff:fe0f:37a5 References: <584564c2-9f64-4965-b045-535cdaf899c0@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <99d7e8ba-9e5a-4881-9132-607d9f16007a@googlegroups.com> Subject: Re: Why are Ada compilers difficult to write ? From: Lucretia Injection-Date: Mon, 01 Oct 2018 18:51:52 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: reader02.eternal-september.org comp.lang.ada:54465 Date: 2018-10-01T11:51:52-07:00 List-Id: On Monday, 1 October 2018 19:09:12 UTC+1, Tucker Taft wrote: > Perhaps the hardest aspect of getting an Ada compiler to pass all of the = ACATS conformance tests is to correctly diagnose all errors, which includes= both compile-time error detection (the so-called "B" tests of the ACATS te= st suite) and the run-time checks, which raise exceptions when some dynamic= semantics rule of the language is violated (the so-called "C" tests of the= ACATS test suite). >=20 > One of the great strengths of Ada compared to other languages is the stri= ctness of the conformance test suite, and its attention to both correctly e= xecuting "good" tests but also correctly detecting compile-time or run-time= problems in "bad" tests. I remember many times when an implementor of an = Ada compiler would announce that they were "almost done," only to discover = that passing all of the B tests took another five person years of effort. >=20 > I would presume that correctly implementing C++ is harder than Ada these = days, given that C++ seems to contain the union of all language features ev= er invented for any language. But relative to C or Pascal, Ada and C++ are= at least one order of magnitude harder, with exceptions, generic templates= , object-oriented programming, and finalization/destructors, as just a few = of the sources of compiler complexity. As there's been talk of creating a new compiler, from someone who's done it= , what advise, apart from "don't do it," would you give to someone consider= ing it?=20 On a separate tangent, would you say look into designing a new language com= pletely? Again, for anyone considering it.